From: Judy Seigel (jseigel@panix.com)
Date: 07/10/03-12:01:46 PM Z
On Thu, 10 Jul 2003, Christina Z. Anderson wrote:
>
> Gum Bichromate Printing, The Practical Photographer Series #18. F. C.
> Lambert, and Thos Harrison Cummings, editors. Chicago: Burke and James,
> May 1905.
> "A Few Notes on Gum Bichromate" by Robert Demachy, pp. 11-13.
>
> That book is full of info on gum.
Some of which is true ! I've got (and treasure) that little book, but
find the quotient of correct info (according to my tests anyway) no higher
than usual. I'll add that the Demachy article there was word for word
printed elsewhere, in a source I don't recall right now, but the repeat
wasn't mentioned -- as they didn't in those days.
As for the sugar formula -- that was a great disappointment to me, and I
still keep the little glass of sugar in the studio as a shrine to failed
hopes. It didn't as far as I could tell make a whit of difference. It
might possibly alter the speed, but the point was to make the emulsion
"melt" more easily. Didn't.
I gather that sugar makes some of those powder-on or dust-off mixes work
by making them sticky. But regular gum --- not. That by the way is IMO
another of the virtues of the 21-step. You see at a glance what's simply
a speed change & what's a character change. Dashes a lot of claims.
And one other point, about Demachy's claims about pre-sizing. Although
theoretically he admits possibility of further coats for himself, he seems
to have done them rarely -- getting his range of tones by judicious
dropping of water on the soft developing print. (Soft sponge held in
hand & carefully squeezed.)
In fact he declared emphatically that multiple gum was a habit of "les
etrangeres," or foreigners, meaning Kuhn & co -- Austrians, Germans --
with the implication that we French can do it all in one. (Digression --
sorry guys, but I was delighted to see in today's paper that the Italians
and Germans are having a tiff. At last, a foodfight the US didn't
start!!!).
I've tested single coat gum on those old papers still available and most
modern papers -- most of which (except for a very few that ALWAYS need a
size) will do a single coat nicely without sizing. That's because the
smooth nap when it's never been wet and surface size left by manufacturer
print very nicely. It's after wetting raises the nap & washes off surface
size the paper tends to need added size.
The Michallet incidentally is still available & made a dandy one coat gum
with no added size -- too bad the INSISTENT laid lines made it useless for
my purposes.... maybe they weren't so bad in earlier version.
cheers,
Judy
>
> Apparently Demachy wrote 6 books, so I'm sure this stuff is elsewhere, too.
> I have only read one, the 1898 version he co-authored with Maskell.
>
> Speaking of which, does anyone know where in the United States, Canada or,
> say, even, London there would be back issues of the British Journal of
> Photography--all years from start to finish--where I would be able to
> research? Or where I could locate a master index of the BJP if there was
> such a thing? The U of MN is missing volumes. It may be because they are
> in an uproar right now with changing systems, as in their catalog they show
> they have those volumes. The BJP is so incredibly full of info I consider
> it, really, about the best source out there. Being a weekly, it is HUGE.
>
> Chris
>
>
> ----- Original Message -----
> From: "Alberto Novo" <alnovo@inwind.it>
> To: "alt-photo-process-l" <alt-photo-process-l@sask.usask.ca>
> Sent: Thursday, July 10, 2003 12:37 AM
> Subject: Re:arcane gum research, beware
>
>
> > > More Demachy notes:
> > > ...
> >
> >
> > Wonderful, Chris!
> > May you give us the full citation of your source?
> >
> > Alberto
> > http://spazioinwind.libero.it/albertonovo/
> >
> > Old Photographic Techniques Group in Italy:
> > http://www.grupponamias.com/
> >
>
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